Low Cost Chemical Feedstocks Using an Improved and Energy Efficient Natural Gas Liquid (NGL) Removal Process, Final Technical Report

Abstract

justifiable at the current natural gas prices), the energy cost to recover NGL using the new technology is about 50% of that of conventional cryogenic technology. Final Progress Report DE-FC36-03GO13150Page 10 AccomplishmentsThis section includes a brief summary of significant accomplishments from the beginning of the project to the present. Items included are significant technical accomplishments, completed major go/no-go decision points and milestones, commercialization successes, patents applied for/received and any other important project highlights.  A computer-simulation-based study was completed by GTI, IIT and GHT to compare the new IROA recovery process for natural-gas liquids (US patent US 6,553,784) with the latest design for Cryogenic Expansion Processes (CEP) (as described in US patent 5,983,664) for four different feed natural gas compositions [C2+: Super Rich (18%), Rich (13%), Lean (8%), and Super Lean (3.7%)] and four levels of C2 recovery (2%, 35%, 70%, and 95%). o The simulation results confirmed that the IROA process, unlike the traditional Refrigerated Oil Absorption process with low ethane recovery, could also recover up to 95% of ethane similar to the Cryogenic Expansion Process. o The IROA has the flexibility to reduce ethane recovery from 95% to 2% during operation with reduced energy consumption.  Based on the annualized overall costs, the IROA was found to be more economical than the CEP in all cases except for higher (95%) recoveries. Since the utility costs associated with IROA decrease with decreasing recovery of NGL, the IROA was found to be more economical than CEP at lower recovery levels.  Further optimization studies identified two major areas of potential energy savings that make the IROA more economical for all levels of recovery: o Maximizing the residue gas exit temperature which could reduce the refrigeration power requirement; and o Separating the NGL condensate from the gas chiller to obtain a partial NGL liquid product which could reduce the power necessary for liquefying the NGL vapor from the Rich Oil Stripper (ROS).  The Phase 1 project results were presented at the 2005 AIChE meeting in Atlanta, GA and to the DOE project review team.  The original economic evaluation was performed using decane as the lean oil. Two alternative solvents have been identified to reduce the solvent costs and to ease modeling.Further testing was performed with kerosene and with a synthetic coal-derived lean oil to determine their applicability.  Task 1 was completed during the second quarter of 2006 in that sufficient relevant physical property and VLE data were collected for preliminary technical verification and design of bench, pilot, and commercial-scale units.  An engineering/fabricator was selected for the design and fabrication of the bench-scale unit.The unit was to be delivered to GTI at the end of January 2007.  A request for quotes was submitted to nine E&C companies for the design and construction of the pilot plant. Three bids were received, but none was acceptable. G...